This can be reflected in the number of Fortune Global 500 companies that exist in the top city/the total number of Fortune Global 500 companies within the country.
The United States has 139 of the Fortune Global 500 companies
And New York City has the largest amount within the U.S, with 19 - or 13.6 %
Compare this with China , who has 46 Fortune Global 500 companies, 30 of which are headquartered in Beijing - 65.2 %
or Japan, who has 71, with 46 headquartered in Tokyo - 64.8 %
or France, who has 39, with 25 headquartered in Paris - 64.1 %
or the United Kingdom, who has 29, with 18 headquartered in London - 62.1%
(but Germany is different, with 37, 6 in Munich - 16.2 %)
All of this is a long way of saying the U.S. is a very decentralized country when it comes to economic and therefore political power. It of course was designed this way by the Founders, primarily to prevent a Casear style popular dictatorship from usurping the ruling class. They knew their Roman history.